Glenn Mulcaire, the private investigator who was jailed in 2007 for intercepting phone messages for the News of the World, has sued News Corp..

The private investigator filed the lawsuit on Tuesday. The grounds of the lawsuit are unclear. Mulcaire is the target of dozens of lawsuits filed by people who claim that he hacked their phones.

Mulcaire was implicated in the phone hacking scandal in 2007 when it was revealed that he had hacked the phones of three aides to the royal family. Investigators found "dozens of notebooks and two computers containing 2,978 complete or partial mobile phone numbers and 91 PIN codes" at Mulcaire's house, according to the New York Times.

In their testimony to Parliament in July, Rupert and James Murdoch said they were unsure if the company was still paying Mulcaire's fees. It subsequently emerged that News Corp. was indeed paying the fees, something Murdoch said the company wouldThey said that they would immediately cease to do/

On Tuesday, James Murdoch revealed that Mulcaire's lawyers had been paid £246,000 (around $400,000) in legal fees.

After the termination of the agreement, Mulcaire challenged News Corp's defense that top editors and company management did not know about phone hacking in July. He released a statement that stressed that he "acted on the instructions of others." The statement contradicted the company's claim that phone hacking was limited to Mulcaire and editor Clive Goodman, who were found guilty of phone hacking in 2007.